What is wrong here?

Example 1

<cfset foo = arrayNew(1)>
<cfset foo[1] = 'bar' />
<cfset foo[2][1] = 'bar2' />
<cfdump var="#foo#" />

<cfset bar = arrayNew() />
<cfset bar[1][1] = 'foo' />
<cfset bar[2][2] = 'foo2' />

<cfdump var="#bar#" />

Example 2

<!--- Create an array with 1 dimension --->
<cfset foo = arrayNew(1)>
<!--- Add a string value to the array --->
<cfset foo[1] = 'bar' />
<!--- Add a struct to the array with struct.1 = bar2 --->
<cfset foo[2][1] = 'bar2' />
<cfdump var="#foo#" />

<!--- Create an array (in Railo) with 1 dimension --->
<cfset bar = arrayNew() />
<!--- Add a struct to the array with struct.hello = foo --->
<cfset bar[1]['hello'] = 'foo' />
<cfdump var="#bar#" />

you need to create the struct and then use an arrayAppend. Otherwise CF thinks that you are trying to access a two dimensional array, and the array was created as one dimensional.

I wrote a blog post explaining what the Gist is here

haha, oops... sorry. It just popped up on my github news feed, and yes you are right "People who develop on Adobe ColdFusion will quickly say that this snippet won't work."

Sorry for missing the point ;)